I got mine from KMDTuning when they were on sale, $1250 for the 1-piece kit which is a killer deal. You can find these kits on Eurosportacc, uspmotorsports, and several others have them as well. As for weight, the stoptech kit I have saved a total of about 9-10 lb's each side over stock, my stock rotors were the 312's so your weight savings would be a touch less.
Even if you don't go stoptech, you can still get their slotted front rotors and some nicer pads like Hawk HPS's or stoptech's and some stainless lines. That'll run you around $400-450 max and that would still improve your setup for sure.
